Sound damping thermoplastic elastomer articles

Abstract

A sound damping article is formed from a thermoplastic elastomer compound that includes styrenic block copolymer, high softening point tackifier, plasticizer, and secondary polymer. The styrenic block copolymer has a Copolymer Tan Delta Peak Temperature and the thermoplastic elastomer compound has a Compound Tan Delta Peak Temperature. The Compound Tan Delta Peak Temperature is greater than the Copolymer Tan Delta Peak Temperature. The sound damping article exhibits useful vibration damping properties while also exhibiting beneficial sound and/or noise damping properties at or above room temperature.

What is claimed is: 
     
       1. A sound damping article formed from a thermoplastic elastomer compound, the compound comprising:
 (a) styrenic block copolymer having a Copolymer Tan Delta Peak Temperature; 
 (b) tackifier having a softening point of at least about 80° C. according to ASTM 6493; 
 (c) plasticizer; and 
 (d) secondary polymer; 
 wherein the compound has a Compound Tan Delta Peak Temperature, and the Compound Tan Delta Peak Temperature is greater than the Copolymer Tan Delta Peak Temperature. 
 
     
     
       2. The sound damping article of  claim 1 , wherein the Copolymer Tan Delta Peak Temperature is greater than −40° C. but less than −10° C. 
     
     
       3. The sound damping article of  claim 1 , wherein the Compound Tan Delta Peak Temperature is at least −10° C. 
     
     
       4. The sound damping article of  claim 1 , wherein the tackifier has a softening point ranging from about 80° C. to about 150° C. according to ASTM 6493. 
     
     
       5. The sound damping article of  claim 1 , wherein the tackifier has a weight average molecular weight ranging from about 400 to about 3,500. 
     
     
       6. The sound damping article of  claim 1 , wherein the tackifier comprises a saturated cyclo-aliphatic amorphous hydrocarbon resin. 
     
     
       7. The sound damping article of  claim 1 , wherein the tackifier is present in an amount ranging from about 20 parts by weight to about 200 parts by weight, per 100 parts by weight of the styrenic block copolymer. 
     
     
       8. The sound damping article of  claim 1 , wherein the tackifier is present in an amount ranging from about 20 parts by weight to about 50 parts by weight, per 100 parts by weight of the styrenic block copolymer. 
     
     
       9. The sound damping article of  claim 1 , wherein the compound further comprises at least one additive selected from the group consisting of adhesion promoters; biocides; anti-fogging agents; anti-static agents; blowing and foaming agents; bonding agents and bonding polymers; dispersants; filler; flame retardants and smoke suppressants; impact modifiers; initiators; lubricants; micas; pigments, colorants and dyes; processing aids; release agents; silanes, titanates and zirconates; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; and combinations of any of the aforementioned additives. 
     
     
       10. The sound damping article of  claim 1 , wherein the compound is essentially free of styrene-(ethylene-ethylene/propylene)-styrene block copolymer and low vinyl styrene-(ethylene/butylene)-styrene block copolymer. 
     
     
       11. The sound damping article of  claim 1 , wherein the styrenic block copolymer is selected from at least one of hydrogenated styrene-isoprene-styrene block copolymer with hydrogenated vinylic isoprene midblock and high vinyl styrene-(ethylene/butylene)-styrene block copolymer. 
     
     
       12. The sound damping article of  claim 11 , wherein the sound damping article, in response to a noise stimulus, produces an effective sound pressure level according to IEC 711 that is at least 80% lower than an effective sound pressure level according to IEC 711 produced by a control article in response to the same noise stimulus, wherein the control article is formed from a control TPE compound that is identical in composition to the thermoplastic elastomer compound except that the control TPE compound is free of high softening point tackifier. 
     
     
       13. A loudspeaker system comprising at least one speaker driver, wherein at least a portion of the speaker driver is at least partially surrounded by at least a portion of the sound damping article of  claim 1 . 
     
     
       14. A loudspeaker system comprising a housing, at least one speaker driver at least partially contained in the housing, and a gasket positioned between at least a portion of the housing and at least a portion of the speaker driver, wherein the gasket comprises the sound damping article of  claim 1 . 
     
     
       15. Wired headphones or earphones comprising a cable, the cable comprising a conductive core at least partially enveloped by a jacket or insulation or both wherein at least one of the jacket or insulation comprises the sound damping article of  claim 1 .